US 3596663 A
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United States Patent Frederick J- Schultz;
Chase W. Lasiter, both 01 Greensboro, N.C.
May 29, 1969 Aug. 3, 1971 Lorillard Corporation New York, N.Y.
lnventors Appl. No. Filed Patented Assignee VENTILATED SMOKING ARTICLE 5 Claims,4 Drawing Figs.
U.S.Cl 131/10 A, l3l/l0.7 Int. CL A24d 01/04,
A24f 13/06 Field oISearch .L 131/10,10
A,9,198,198 A, 15 B  References Cited UNITED STATES PATENTS 269,256 12/1882 Bourgeois 131/15 B UX 3,396,733 8/1968 Allseits et a1. 131/10.5 3,490,461 1/1970 Osmalon et a1. 131/9 X FOREIGN PATENTS 240,650 9/1962 Australia 131/9 668,052 8/1963 Canada 131/9 938,902 10/1963 Great Britain 131/10 A Primary Examiner-Aldrich Medbery Assistant Examiner-J. F. Pitrelli Auorney-Brurnbaugh, Grayes, Donohue & Raymond ABSTRACT: The admission of outside air to a tobacco smoke filter is enhanced by providing a corrugated wrapper around the filter plug, thereby to define a multiplicity of passages for conducting air admitted through the tipping paper over a relatively large portion of the surface of the filter plug.
PATENTED AUG 3 I97! 3, 596, 663
INVENTORS. FREDERICK J. SCHULTZ 8| CHASE W. LASSITER their ATTORNEYS VENTILATED SMOKING ARTICLE BACKGROUND or THE INVENTION This invention relates to tobacco smoke filters of the ventilated type and, in particular, to ventilated filters for use in cigarettes.
A relatively recent development in the cigarette industry is the so-called ventilated filter. A ventilated filter may be defined as a filter which is constructed in a manner such that outside air is drawn in through the filter and blended with the smoke for admission to the smokers mouth. The ventilated filter makes it possible to use a higher density filtering medium for removal of greater quantities of smoke while not reducing the draw that the smoker expects.
The usual form of ventilated filter comprises one or more rows of tiny holes in the tipping paper located in a region overlying the filter plug. Ordinarily, the filter plug in both conventional and ventilated filters, is enclosed in a paper wrapper, and in the case of ventilated filters, the wrapper is either perforated or is formed of a porous paper so that air admitted through the small holes in the tipping paper can pass through the wrapper to the filter plug.
It is apparent that ventilated filters of the construction described above provide a relatively high restriction to the entry of air to the filter. First of all, the admission of air is limited to the holes through the tipping paper. Secondly, by reason of the tight wrapping of the tipping paper around the filter-plug wrapper and the wrapper around the filter plug, the admission of air is limited to a relatively small portion of the surface area of the filter plug, such portion of the surface area of the filter plug, such portion being not much greater than the total area of the holes.
SUMMARY OF THE INVENTION There is provided, in accordance with the invention, a ventilated filter that significantly reduces the restriction of the passage of air to the filtering medium. More particularly, a ventilated filter, according to the invention, comprises a filter plug, which may be fibrous or particulate material or may be a composite or combination of fibrous and particulate material, and will usually have a porous filter wrapper around it. A tipping paper is wrapped around the filter plug and a portion of the tobacco body of the cigarette to join the filter plug to the cigarette body. The tipping paper is constructed to admit air to the filter plug, such as by the provision of tiny holes through it in a region overlying the filter plug. In accordance with the invention, a significant increase in the passage of air from the tipping paper holes into the filter plug is afforded by providing a corrugated inner wrapper between the filter plug and the tipping paper. The corrugations provide a multiplicity of passages adjacent to the filter plug and in communication with the air inlet holes in the tipping paper so that air entering through the perforations is spread over a relatively large area of the filter plug and is communicated over a considerably increased surface area of the filter plug. Thus, the invention makes it possible to lower the pressure drop at the exit end of the filter, as compared to essentially the same filter construction without a corrugated inner wrapper, or to provide the same pressure drop with a less restricted airflow to the filter, thus enabling a denser filter medium to be used.
DESCRIPTION OF THE DRAWINGS For a better understanding of the invention,reference may be made to the following description of exemplary embodiments, taken in conjunction with the figures of the accompanying drawings, in which:
FIG. 1 is a pictorial view of a cigarette having the improved ventilated filter, portions of the components of the cigarette being broken away more clearly to show the construction;
FIG. 2 is a pictorial view of a cigarette having the improved ventilated filter and also provided with a built-in mouthpiece, portions again being broken away;
FIG. 3 is an end cross-sectional view taken through the filter plug section of the cigarettes of either FIG. 1 or FIG. 2, the view being on an enlarged scale relative to FIGS. 1 and 2 and being taken generally along the plane represented by the lines 3-3 in FIGS. 1 and 2; and
FIG. 4 is a further enlarged end sectional view of a segment of the filter.
DESCRIPTION OF EXEMPLARY EMBODIMENTS The embodiment of FIG. 1 comprises, of course, a cylindrical rod 10 of tobacco encased within a paper wrapper l2 and constituting the body of the cigarette. In end-to-end relation to one end of the tobacco rod 10 is a filter plug 14, which may be any appropriate smoke filter medium. The drawings show a fibrous medium. Today's conventional fibrous filter plugs are manufactured with a paper wrapper (not shown), and for a ventilated filter, the filter plug wrapper is made of porous paper or apaper formed with perforations. For purposes of the following description any reference to the filter plug will mean the filter plug and its wrapper, if it has one.
The filter plug 14 is enclosed within an inner band or wrapper 16 of a material that is permeable to air either by vir- 0.05 mm. 27-33 g/m l.9 sec/50 cc. air.
Thickness Density Greiner Porosity The filter plug 14 and the wrapper 16 are attached to the cigarette body 10 with a conventional tipping paper 18 which encompasses the entire filter plug and overlaps a portion of the cigarette body.
The embodiment of FIG. 2 is the same as the embodiment of FIG. 1 except for the lengths of the filter plug 14a and the inner wrapper 16a and the inclusion in end-to-end relation at the smoking end of the cigarette of a mouthpiece 20. The mouthpiece may be a cylindricalplastic extrusion formed with an internal structure providing support for the cylindrical body, and may, for example, be of the construction described as shown in U. S. Pat. No. 3,396,733. The inner wrapper 16a is wrapped around both the filter plug and the mouthpiece and serves to join them together for handling as a composite unit in tipping machinery.
The filter structures of the embodiments of both FIGS. 1 and 2 provide for the admission of air into the filter and thence to the smokers mouth by, first of all, conduction of air through the tipping paper 18 by way of a multiplicity of small holes 22 spaced circumferentially around the tipping paper 18 in a region overlying the filter plug 14 (or 14a). The number and size of the holes is established so that a desired draw through the cigarette, with due consideration for the pressure loss of the smoke passing through the filter, is obtained. In other words, the filter plug may have a'pressure loss in excess of that which would provide a desirable product, from the smokers standpoint, and the perforations provide for the admission of air to the filter and the flow of air with the smoke to the smokers mouth, the airflow compensating for the increased pressure drop across the filter.
In accordance with the invention, the air drawn in through the holes 22 when the cigarette is smoked is enabled to pass more readily into the filter plug material by forming corrugations in the inner wrapper l6 prior-to assembling it onto the filter plug. The corrugations can be produced in various ways, such as by passing the strip for the wrapper paper between two grooved or screw-threaded rollers. The depth and pitch of the corrugations in the paper is controlled by the geometry of the forming rollers and the pressure applied to them. When threaded rollers are used, one has a right-handithread and the other a left-hand thread. and they are rotated in opposite directions so that the surfaces of both move with, and in fact, feed the paper through them. The number of corrugations is, of course, controlled by the number of grooves or threads on 16 do not afford any opportunity for channeling or bypassing of smoke along the corrugations. The end of the filter wrapper 16 is an end-to-end engagement with the end of the cigarette body wrapper 12, and therefore the ends of the air passages the forming rollers and may range from about 10 to about 60 constituted by the corrugations of the wrapper 16 are closed per inch. The depth of the corrugations may range from about off. 0.01 to 0.06 inch and is related somewhat to the pitch of the Tests have been conducted to determine the contribution of corrugations. the corrugationed wrapper to a ventilated-type filter structure. The pitch of the corrugations is desirably such that the The tests were made on control cigarettes and sample number of corrugations approximates the number of holes cigarettes, the controls and the samples being of identical conthrough the tipping paper so that most of the holes will be exstruction except that the samples incorporated a plain (uncorposed to an open area between the points of contact between rugated) wrapper of the same material around the filter plug. the tipping paper 18 and the wrapper 16. However, the corru- The cigarettes were tested on conventional mechanical smokgations should not have a pitch equal to the number of ventiing machines, and the pertinent physical properties and the lated holes, since equality in that respect would present a risk is results of the smoking tests are set forth in table I below. of an Ventilation holes being covered by the Outer loops of the One series of tests involved smoking the cigarettes with the wrapper m some clgarettes Produced; holes taped closed so as to provide a measure of the degree of A5 is pp from FIG Particularly the eoh'ugatlohs similarity between the controls and samples apart from the Provide a multiplicity of geherahy lengthwise airspaees 20 ventilation feature. It is apparent from the results that the cong the length of the wrapper and in communication with trols and samples were quite similar. With the holes open, the outside through the Ventilation holes Thus, however, the draw was improved, and the amounts of tar and drawn through the holes is distributed along the Passages and nicotine were substantially lower, as compared to the results flows through the Porous or lilel'fol'ated Wrapper 16 over 3 obtained when the holes were taped. Moreover, the tests telativel) hh'ge area of the Surface of the filter P The P 25 showed clearly that the draw was improved and tar and portuhity for to P relatively freely into the filter P is nicotine were significantly reduced in the samples, as comq y greatly enhanced, as Compared to the eehvehpared to the controls, thus demonstrating that the invention tioha] eohsth-tetioh i which a layer of P P overlying the provides material improvements in draw, tar and nicotine. filter plug closely en gages the filter plug surface and is closely Samples A and B1 included corrugated finer plug wrappers engaged by the hppmg P The net effect of Such closely 0 made of paper having the specifications given above corruengaged layers of wrapping material is a relatively nonporous gated b passing throu rolls having 24 threads er inch and laminate, whereas the interposition of the corrugated wrapper a threa depth of 0.02 7 inch urged together wit a nip presopens the structure and spreads the air over a much larger sure on the paper of 12 lbs/inch. Sample B2 had awrapper of area of the filter plug. the same paper corrugated on the same equipment but with a In addition to providing an increased surface for the air to nip pressure of 13 lbs/inch and thus sample B2 had a slightly enter the filter, the corrugations of the wrapper increase the greater depth of corrugation than samples A and B1.
'TABLE I Cigarette Smoking Cigarette pressure drop Nicotine time weight (g.) (mm. H2O) Tar (mg.) (mg.) (min.)
Control A 1. 074 120 14. 8 72 6. 8 Sample A 1. 075 110 14. s .77 7.2 Holes open:
Control A. 1.071 110 11.0 .58 7. 2 Sample A 1 8. 2 48 8. 0 Control A, percent reduction. 7 19.4 Sample A, percent reduction. .6 37. 7
Control A, 33 mm. butt 10.4
Sample A, 33 mm. butt 7. 7 Holes taped:
Control B 1. 096 132 16. 4
Sample B1. 1.085 132 15. 4
Sample B2 1.088 140 15. 4 Holes open:
Control B 1 096 132 15. 4
Sample B1. 1.085 126 12.3
Sample B2 1.088 126 11.2
Control 13, percent reduction 6. 1
Sample B1, percent reduction 20.1
Sample B2, percent reduction 27.3
Control 13, 33 mm. butt Sample B1, 33 mm. butt Sample B2, 33 mm. butt l Corrected 'IPM.
1. A smoking article comprising an elongated body of tobacco, a filter mass in end-to-end relation to the tobacco body, a separate wrapper of air-permeable material surrounding and directly engaging the filter mass, and a tipping paper surrounding the air-permeable wrapper and a portion of the tobacco body and secured to them to join them together, the tipping paper having means overlying the air-permeable wrapper for admitting air to the filter air-permeable wrapper. and the air-permeable wrapper being corrugated to increase the permeable surface area thereof to facilitate conducting air admitted through the tipping paper to the filter mass.
2. A smoking article according to claim I wherein the means for admitting air through the tipping paper comprises at least one generally circumferential row of spaced-apart perforations overlying the filter mass, and wherein the number of corrugations in the air-permeable wrapper corresponds generally to the number of such perforations in the row.
3. A smoking article according to claim 1 wherein the corrugations in the air-permeable wrapper range from about ID to about 60 per inch in number and have an overall depth in the range of from about 0.01 inch to about 0.06 inch.
4. A smoking article according to claim 1 further comprising a mouthpiece in end-to-end relation to the filter mass.
5. A smoking article comprising an elongated body of tobacco, a filter mass in end-to-end relation to the tobacco body, a wrapper of porous paper surrounding the filter mass and a tipping paper surrounding the paper wrapper and a portion of the tobacco body and secured to them to join them together, the tipping paper having at least one generally circumferential row of perforations overlying the filter mass and the paper wrapper, and the paper wrapper being corrugated generally lengthwise of the filter mass with corrugations in the range of from about 10 to about per inch in number and having an overall depth of from about 0.01 inch to 0.06 inch thereby to define a multiplicity of passages for conducting air admitted through the tipping paper to the filter mass, the number of corrugations in the wrapper corresponding generally to the number of such perforations in the row.